Month

65 Matching Results

Results open in a new window/tab.

Novel Approaches to High-Efficiency III-V Nitride Heterostructure Emitters for Next-Generation Lighting Applications (open access)

Novel Approaches to High-Efficiency III-V Nitride Heterostructure Emitters for Next-Generation Lighting Applications

We report research activities and technical progress on the development of high-efficiency long wavelength ({lambda} {approx} 540nm) green light emitting diodes which covers whole years of the three-year program 'Novel approaches to high-efficiency III-V nitride heterostructure emitters for next-generation lighting applications'. The research activities were focused on the development of p-type layer that has less/no detrimental thermal annealing effect on as well as excellent structural and electrical properties and the development of green LED active region that has superior luminescence quality for {lambda}{approx}540nm green LEDs. We have also studied (1) the thermal annealing effect on blue and green LED active region during the p-type layer growth; (2) the effect of growth parameters and structural factors for LED active region on electroluminescence properties; (3) the effect of substrates and orientation on electrical and electro-optical properties of green LEDs. As a progress highlight, we obtained green-LED-active-region-friendly In{sub 0.04}Ga{sub 0.96}N:Mg exhibiting low resistivity with higher hole concentration (p=2.0 x 10{sup 18} cm{sup -3} and a low resistivity of 0.5 {omega}-cm) and improved optical quality green LED active region emitting at {approx}540nm by electroluminescence. The LEDs with p-InGaN layer can act as a quantum-confined Stark effect mitigation layer by reducing strain in the QW. …
Date: June 30, 2007
Creator: Dupuis, Russell
Object Type: Report
System: The UNT Digital Library
Development of a Geologic Exploration Model foe the Permo-Pennsylvanian Petroleum System in South-Central Montana (open access)

Development of a Geologic Exploration Model foe the Permo-Pennsylvanian Petroleum System in South-Central Montana

Eolian sands are the main Pennsylvanian Tensleep Sandstone reservoir rocks, and were deposited in a near-shore environment interbedded with near-shore marine and sabkha calcareous and dolomitic rocks. Within the Tensleep, numerous cycles are characterized by basal marine or sabkha calcareous sandstone or dolomitic sandstone overlain by porous and permeable eolian sandstone, which in turn is capped by marine sandstone. The cycles represent the interplay of near-shore marine, sabkha, and eolian environments. On the west side of the project area, both the lower and upper Tensleep are present and the total thickness reaches a maximum of about 240 ft. The lower Tensleep is 100 to 120 ft thick and consists of a sequence of repeating cycles of limey shallow marine sandstone, sandy limestone, and sandy dolomite. The upper Tensleep is generally characterized by cycles of sandy limestone or dolomite, overlain by light-colored, eolian dune sandstone capped by marine limey sandstone. In the central and eastern parts of the project area, only the lower Tensleep is present, but here eolian sandstones are in cycles much like those in the west in the upper Tensleep. The lower Tensleep is quite variable in thickness, ranging from about 25 ft to over 200 ft. Oil …
Date: June 30, 2007
Creator: Lopez, David A.
Object Type: Report
System: The UNT Digital Library
TiO2 Nanoparticles as a Soft X-ray Molecular Probe (open access)

TiO2 Nanoparticles as a Soft X-ray Molecular Probe

With the emergence of soft x-ray techniques for imaging cells, there is a pressing need to develop protein localization probes that can be unambiguously identified within the region of x-ray spectrum used for imaging. TiO2 nanocrystal colloids, which have a strong absorption cross-section within the "water-window" region of x-rays, areideally suited as soft x-ray microscopy probes. To demonstrate their efficacy, TiO2-streptavidin nanoconjugates were prepared and subsequently labeled microtubules polymerized from biotinylated tubulin. The microtubules were imaged using scanning transmission x-ray microscopy (STXM), and the TiO2 nanoparticle tags were specifically identified using x-ray absorption near edge spectroscopy (XANES). These experiments demonstrate that TiO2 nanoparticles are potential probes for protein localization analyses using soft x-ray microscopy.
Date: June 30, 2007
Creator: Larabell, Carolyn; Ashcroft, Jared M.; Gu, Weiwei; Zhang, Tierui; Hughes, Steven M.; Hartman, Keith B. et al.
Object Type: Article
System: The UNT Digital Library
Carbon Dioxide Separation from Flue Gas by Phase Enhanced Absorption (open access)

Carbon Dioxide Separation from Flue Gas by Phase Enhanced Absorption

A new process, phase enhanced absorption, was invented. The method is carried out in an absorber, where a liquid carrier (aqueous solution), an organic mixture (or organic compound), and a gas mixture containing a gas to be absorbed are introduced from an inlet. Since the organic mixture is immiscible or at least partially immiscible with the liquid carrier, the organic mixture forms a layer or small parcels between the liquid carrier and the gas mixture. The organic mixture in the absorber improves mass transfer efficiency of the system and increases the absorption rate of the gas. The organic mixture serves as a transportation media. The gas is finally accumulated in the liquid carrier as in a conventional gas-liquid absorption system. The presence of the organic layer does not hinder the regeneration of the liquid carrier or recovery of the gas because the organic layer is removed by a settler after the absorption process is completed. In another aspect, the system exhibited increased gas-liquid separation efficiency, thereby reducing the costs of operation and maintenance. Our study focused on the search of the organic layer or transportation layer to enhance the absorption rate of carbon dioxide. The following systems were studied, (1) …
Date: June 30, 2007
Creator: Fout, Tim
Object Type: Report
System: The UNT Digital Library
Surface Area, Volume, Mass, and Density Distributions for Sized Biomass Particles (open access)

Surface Area, Volume, Mass, and Density Distributions for Sized Biomass Particles

This final technical report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period July 01, 2004 to June 30, 2007 which covers the entire performance period of the project. 25 individual biomass particles (hardwood sawdust AI14546 in the size range of 100-200 microns) were levitated in an electrodynamic balance (EDB) and their external surface area, volume, and drag coefficient/mass (C{sub d}/m) ratios were characterized applying highly specialized video based and high-speed diode array imaging systems. Analysis methods were employed using shape and drag information to calculate mass and density distributions for these particles. Results of these measurements and analyses were validated by independent mass measurements using a particle weighing and counting technique. Similar information for 28 PSOC 1451D bituminous coal particles was retrieved from a previously published work. Using these two information, density correlations for coal/biomass blends were developed. These correlations can be used to estimate the density of the blend knowing either the volume fraction or the mass fraction of coal in the blend. The density correlations presented here will be useful in predicting the burning rate of coal/biomass blends in cofiring combustors. Finally, a discussion on technological impacts and economic projections of burning …
Date: June 30, 2007
Creator: Sampath, Ramanathan
Object Type: Report
System: The UNT Digital Library
Development of Superior Sorbents for Separation of CO2 from Flue Gas at a Wide Temperature Range During Coal Combustion (open access)

Development of Superior Sorbents for Separation of CO2 from Flue Gas at a Wide Temperature Range During Coal Combustion

In chapter 1, the studies focused on the development of novel sorbents for reducing the carbon dioxide emissions at high temperatures. Our studies focused on cesium doped CaO sorbents with respect to other major flue gas compounds in a wide temperature range. The thermo-gravimetric analysis of sorbents with loadings of CaO doped on 20 wt% cesium demonstrated high CO{sub 2} sorption uptakes (up to 66 wt% CO{sub 2}/sorbent). It is remarkable to note that zero adsorption affinity for N{sub 2}, O{sub 2}, H{sub 2}O and NO at temperatures as high as 600 C was observed. For water vapor and nitrogen oxide we observed a positive effect for CO{sub 2} adsorption. In the presence of steam, the CO{sub 2} adsorption increased to the highest adsorption capacity of 77 wt% CO{sub 2}/sorbent. In the presence of nitrogen oxide, the final CO{sub 2} uptake remained same, but the rate of adsorption was higher at the initial stages (10%) than the case where no nitrogen oxide was fed. In chapter 2, Ca(NO{sub 3}){sub 2} {center_dot} 4H{sub 2}O, CaO, Ca(OH){sub 2}, CaCO{sub 3}, and Ca(CH{sub 3}COO){sub 2} {center_dot} H{sub 2}O were used as precursors for synthesis of CaO sorbents on this work. The sorbents prepared …
Date: June 30, 2007
Creator: Smirniotis, Panagiotis G.
Object Type: Report
System: The UNT Digital Library
Argonne Liquid-Metal Advanced Burner Reactor : Components and In-Vessel System Thermal-Hydraulic Research and Testing Experience - Pathway Forward. (open access)

Argonne Liquid-Metal Advanced Burner Reactor : Components and In-Vessel System Thermal-Hydraulic Research and Testing Experience - Pathway Forward.

This white paper provides an overview and status report of the thermal-hydraulic nuclear research and development, both experimental and computational, conducted predominantly at Argonne National Laboratory. Argonne from the early 1970s through the early 1990s was the Department of Energy's (DOE's) lead lab for thermal-hydraulic development of Liquid Metal Reactors (LMRs). During the 1970s and into the mid-1980s, Argonne conducted thermal-hydraulic studies and experiments on individual reactor components supporting the Experimental Breeder Reactor-II (EBR-II), Fast Flux Test Facility (FFTF), and the Clinch River Breeder Reactor (CRBR). From the mid-1980s and into the early 1990s, Argonne conducted studies on phenomena related to forced- and natural-convection thermal buoyancy in complete in-vessel models of the General Electric (GE) Prototype Reactor Inherently Safe Module (PRISM) and Rockwell International (RI) Sodium Advanced Fast Reactor (SAFR). These two reactor initiatives involved Argonne working closely with U.S. industry and DOE. This paper describes the very important impact of thermal hydraulics dominated by thermal buoyancy forces on reactor global operation and on the behavior/performance of individual components during postulated off-normal accident events with low flow. Utilizing Argonne's LMR expertise and design knowledge is vital to the further development of safe, reliable, and high-performance LMRs. Argonne believes there remains …
Date: June 30, 2007
Creator: Kasza, K.; Grandy, C.; Chang, Y. & Khalil, H.
Object Type: Report
System: The UNT Digital Library
Microhole High-Pressure Jet Drill for Coiled Tubing (open access)

Microhole High-Pressure Jet Drill for Coiled Tubing

Tempress Small Mechanically-Assisted High-Pressure Waterjet Drilling Tool project centered on the development of a downhole intensifier (DHI) to boost the hydraulic pressure available from conventional coiled tubing to the level required for high-pressure jet erosion of rock. We reviewed two techniques for implementing this technology (1) pure high-pressure jet drilling and (2) mechanically-assisted jet drilling. Due to the difficulties associated with modifying a downhole motor for mechanically-assisted jet drilling, it was determined that the pure high-pressure jet drilling tool was the best candidate for development and commercialization. It was also determined that this tool needs to run on commingled nitrogen and water to provide adequate downhole differential pressure and to facilitate controlled pressure drilling and descaling applications in low pressure wells. The resulting Microhole jet drilling bottomhole assembly (BHA) drills a 3.625-inch diameter hole with 2-inch coil tubing. The BHA consists of a self-rotating multi-nozzle drilling head, a high-pressure rotary seal/bearing section, an intensifier and a gas separator. Commingled nitrogen and water are separated into two streams in the gas separator. The water stream is pressurized to 3 times the inlet pressure by the downhole intensifier and discharged through nozzles in the drilling head. The energy in the gas-rich stream …
Date: June 30, 2007
Creator: Theimer, Ken & Kolle, Jack
Object Type: Report
System: The UNT Digital Library
Exploitation and Optimization of Reservoir Performance in Hunton Formation, Oklahoma (open access)

Exploitation and Optimization of Reservoir Performance in Hunton Formation, Oklahoma

Hunton formation in Oklahoma has been the subject of attention for the last ten years. The new interest started with the drilling of the West Carney field in 1995 in Lincoln County. Subsequently, many other operators have expanded the search for oil and gas in Hunton formation in other parts of Oklahoma. These fields exhibit many unique production characteristics, including: (1) decreasing water-oil or water-gas ratio over time; (2) decreasing gas-oil ratio followed by an increase; (3) poor prediction capability of the reserves based on the log data; and (4) low geological connectivity but high hydrodynamic connectivity. The purpose of this investigation is to understand the principal mechanisms affecting the production, and propose methods by which we can optimize the production from fields with similar characteristics.
Date: June 30, 2007
Creator: Kelkar, Mohan
Object Type: Report
System: The UNT Digital Library
An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration (open access)

An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration

A deep drilling research program titled 'An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration' was conducted at TerraTek's Drilling and Completions Laboratory. Drilling tests were run to simulate deep drilling by using high bore pressures and high confining and overburden stresses. The purpose of this testing was to gain insight into practices that would improve rates of penetration and mechanical specific energy while drilling under high pressure conditions. Thirty-seven test series were run utilizing a variety of drilling parameters which allowed analysis of the performance of drill bits and drilling fluids. Five different drill bit types or styles were tested: four-bladed polycrystalline diamond compact (PDC), 7-bladed PDC in regular and long profile, roller-cone, and impregnated. There were three different rock types used to simulate deep formations: Mancos shale, Carthage marble, and Crab Orchard sandstone. The testing also analyzed various drilling fluids and the extent to which they improved drilling. The PDC drill bits provided the best performance overall. The impregnated and tungsten carbide insert roller-cone drill bits performed poorly under the conditions chosen. The cesium formate drilling fluid outperformed all other drilling muds when drilling in …
Date: June 30, 2007
Creator: TerraTek
Object Type: Report
System: The UNT Digital Library
Final Report : Groundwater Monitoring at Morrill, Kansas, in September 2005 and March 2006, With Expansion of the Monitoring Network in January 2006. (open access)

Final Report : Groundwater Monitoring at Morrill, Kansas, in September 2005 and March 2006, With Expansion of the Monitoring Network in January 2006.

This document reports the results of groundwater monitoring in September 2005 and March 2006 at the grain storage facility formerly operated at Morrill, Kansas, by the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA). These activities were the first and second twice yearly sampling events of the two-year monitoring program approved by the CCC/USDA and Kansas Department of Health and Environment (KDHE) project managers. The monitoring network sampled in September 2005 consisted of 9 monitoring wells (MW1S-MW5S and MW1D [installed in the mid 1990s] and MW6S-MW8S [installed in 2004]), plus 3 private wells (Isch, Rillinger, and Stone). The groundwater samples collected in this first event were analyzed for volatile organic compounds (VOCs), dissolved hydrogen, and additional groundwater parameters to aid in evaluating the potential for reductive dechlorination processes. After the monitoring in September 2005, Argonne recommended expansion of the initial monitoring network. Previous sampling (August 2004) had already suggested that the initial network was inadequate to delineate the extent of the carbon tetrachloride plume. With the approval of the CCC/USDA and KDHE project managers, the monitoring network was expanded in January 2006 through the installation of 3 additional monitoring wells (MW9S-MW11S). Details of the monitoring well installations are …
Date: June 30, 2007
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Low-Cost Options for Moderate Levels of Mercury Control (open access)

Low-Cost Options for Moderate Levels of Mercury Control

The report is broken into three sections, this is Part 3 of 3.
Date: June 30, 2007
Creator: Sjostrom, Sharon
Object Type: Report
System: The UNT Digital Library
4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir (open access)

4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate …
Date: June 30, 2007
Creator: Miller, Richard D.; Raef, Abdelmoneam E.; Byrnes, Alan P. & Harrison, William E.
Object Type: Report
System: The UNT Digital Library
Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer (open access)

Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer

University of Utah's project entitled 'Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer' (DOE Cooperative Agreement DE-FC26-02NT41490) was developed in response to a solicitation released by the U.S. Department of Energy in December 2001, requesting proposals for projects targeted towards black liquor/biomass gasification technology support research and development. Specifically, the solicitation was seeking projects that would provide technical support for Department of Energy supported black liquor and biomass gasification demonstration projects under development at the time.
Date: June 30, 2007
Creator: Whitty, Kevin
Object Type: Report
System: The UNT Digital Library
RP-5 Renewable Energy Efficiency Project (open access)

RP-5 Renewable Energy Efficiency Project

This is the final technical report for the RP-5 Renewable Energy Efficiency Project (REEP). The report summarizes, in a comprehensive manner, all the work performed during the award period extending between July 12, 2002 and June 30, 2007. This report has been prepared in accordance with the Department of Energy (DOE) Guidelines and summarizes all of the activities that occurred during the award period. The RP-5 Renewable Energy Efficiency Project, under development by the Inland Empire Utilities Agency (IEUA), is comprised of a series of full-scale demonstration projects that will showcase innovative combinations of primary and secondary generation systems using methane gas derived from local processing of biosolids, dairy manure and other organic material. The goal of the project is to create renewable energy-based generation systems with energy efficiencies 65% or more. The project was constructed at the 15 MGD Regional Wastewater Treatment Plant No. 5 located in the City of Chino in California where the Agency has constructed its new energy-efficient (platinum-LEED rating) headquarters building. Technologies that were featured in the project include internal combustion engines (ICE), absorption chillers, treatment plant secondary effluent cooling systems, heat recovery systems, thermal energy storage (TES), Organic Rankine Cycle (ORC) secondary power generation …
Date: June 30, 2007
Creator: Clifton, Neil; Wall, Dave & Zughbi, Jamal
Object Type: Report
System: The UNT Digital Library
Argonne's Laboratory Computing Resource Center : 2005 Annual Report. (open access)

Argonne's Laboratory Computing Resource Center : 2005 Annual Report.

Argonne National Laboratory founded the Laboratory Computing Resource Center in the spring of 2002 to help meet pressing program needs for computational modeling, simulation, and analysis. The guiding mission is to provide critical computing resources that accelerate the development of high-performance computing expertise, applications, and computations to meet the Laboratory's challenging science and engineering missions. The first goal of the LCRC was to deploy a mid-range supercomputing facility to support the unmet computational needs of the Laboratory. To this end, in September 2002, the Laboratory purchased a 350-node computing cluster from Linux NetworX. This cluster, named 'Jazz', achieved over a teraflop of computing power (10{sup 12} floating-point calculations per second) on standard tests, making it the Laboratory's first terascale computing system and one of the fifty fastest computers in the world at the time. Jazz was made available to early users in November 2002 while the system was undergoing development and configuration. In April 2003, Jazz was officially made available for production operation. Since then, the Jazz user community has grown steadily. By the end of fiscal year 2005, there were 62 active projects on Jazz involving over 320 scientists and engineers. These projects represent a wide cross-section of Laboratory …
Date: June 30, 2007
Creator: Bair, R. B.; Coghlan, S. C; Kaushik, D. K.; Riley, K. R.; Valdes, J. V. & Pieper, G. P.
Object Type: Report
System: The UNT Digital Library
Study of the microbunching instability in single-pass systemsusing a direct 2D Vlasov solver (open access)

Study of the microbunching instability in single-pass systemsusing a direct 2D Vlasov solver

We apply a recently developed Vlasov solver to the study ofthemicrobunching instability generated by shot noise in the beamdeliverysystems of x-ray Free Electron Lasers (FELs). We discusstwo latticespresently under consideration for the FEL FERMI project at Elettra andshow that at least one of the two lattices appears capable of deliveringa beam with the desired quality in the longitudinal phasespace.
Date: June 30, 2007
Creator: Venturini, Marco
Object Type: Article
System: The UNT Digital Library
Performance, Efficiency, and Emissions Characterization of Reciprocating Internal Combustion Engines Fueled with Hydrogen/Natural Gas Blends (open access)

Performance, Efficiency, and Emissions Characterization of Reciprocating Internal Combustion Engines Fueled with Hydrogen/Natural Gas Blends

Hydrogen is an attractive fuel source not only because it is abundant and renewable but also because it produces almost zero regulated emissions. Internal combustion engines fueled by compressed natural gas (CNG) are operated throughout a variety of industries in a number of mobile and stationary applications. While CNG engines offer many advantages over conventional gasoline and diesel combustion engines, CNG engine performance can be substantially improved in the lean operating region. Lean operation has a number of benefits, the most notable of which is reduced emissions. However, the extremely low flame propagation velocities of CNG greatly restrict the lean operating limits of CNG engines. Hydrogen, however, has a high flame speed and a wide operating limit that extends into the lean region. The addition of hydrogen to a CNG engine makes it a viable and economical method to significantly extend the lean operating limit and thereby improve performance and reduce emissions. Drawbacks of hydrogen as a fuel source, however, include lower power density due to a lower heating value per unit volume as compared to CNG, and susceptibility to pre-ignition and engine knock due to wide flammability limits and low minimum ignition energy. Combining hydrogen with CNG, however, overcomes …
Date: June 30, 2007
Creator: Chapman, Kirby S. & Patil, Amar
Object Type: Report
System: The UNT Digital Library
SciDAC Visualization and Analytics Center for Enabling Technologies (open access)

SciDAC Visualization and Analytics Center for Enabling Technologies

The Visualization and Analytics Center for EnablingTechnologies (VACET) focuses on leveraging scientific visualization andanalytics software technology as an enabling technology for increasingscientific productivity and insight. Advances in computational technologyhave resulted in an 'information big bang,' which in turn has created asignificant data understanding challenge. This challenge is widelyacknowledged to be one of the primary bottlenecks in contemporaryscience. The vision of VACET is to adapt, extend, create when necessary,and deploy visual data analysis solutions that are responsive to theneeds of DOE'scomputational and experimental scientists. Our center isengineered to be directly responsive to those needs and to deliversolutions for use in DOE's large open computing facilities. The researchand development directly target data understanding problems provided byour scientific application stakeholders. VACET draws from a diverse setof visualization technology ranging from production quality applicationsand application frameworks to state-of-the-art algorithms forvisualization, analysis, analytics, data manipulation, and datamanagement.
Date: June 30, 2007
Creator: Bethel, E. Wes; Johnson, Chris; Joy, Ken; Ahern, Sean; Pascucci, Valerio; Childs, Hank et al.
Object Type: Article
System: The UNT Digital Library
Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications (open access)

Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

Cerium gadolinium oxide (CGO) has been identified as an acceptable solid oxide fuel cell (SOFC) electrolyte at temperatures (500-700 C) where cheap, rigid, stainless steel interconnect substrates can be used. Unfortunately, both the high sintering temperature of pure CGO, >1200 C, and the fact that constraint during sintering often results in cracked, low density ceramic films, have complicated development of metal supported CGO SOFCs. The aim of this work was to find new sintering aids for Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95}, and to evaluate whether they could be used to produce dense, constrained Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} films at temperatures below 1000 C. To find the optimal sintering aid, Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} was doped with a variety of elements, of which lithium was found to be the most effective. Dilatometric studies indicated that by doping CGO with 3mol% lithium nitrate, it was possible to sinter pellets to a relative density of 98.5% at 800 C--a full one hundred degrees below the previous low temperature sintering record for CGO. Further, it was also found that a sintering aid's effectiveness could be explained in terms of its size, charge and high temperature mobility. A closer examination of lithium doped Ce0.9Gd0.1O1.95 indicated that …
Date: June 30, 2007
Creator: Nicholas, Jason.D.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
SGP Cloud and Land Surface Interaction Campaign (CLASIC): Science and Implementation Plan (open access)

SGP Cloud and Land Surface Interaction Campaign (CLASIC): Science and Implementation Plan

The Cloud and Land Surface Interaction Campaign is a field experiment designed to collect a comprehensive data set that can be used to quantify the interactions that occur between the atmosphere, biosphere, land surface, and subsurface. A particular focus will be on how these interactions modulate the abundance and characteristics of small and medium size cumuliform clouds that are generated by local convection. These interactions are not well understood and are responsible for large uncertainties in global climate models, which are used to forecast future climate states. The campaign will be conducted from June 8 to June 30, 2007, at the U.S. Department of Energy’s Atmospheric Radiation Measurement Climate Research Facility Southern Great Plains site. Data will be collected using eight aircraft equipped with a variety of specialized sensors, four specially instrumented surface sites, and two prototype surface radar systems. The architecture of Cloud and Land Surface Interaction Campaign includes a high-altitude surveillance aircraft and enhanced vertical thermodynamic and wind profile measurements that will characterize the synoptic scale structure of the clouds and the land surface within the Atmospheric Radiation Measurement Climate Research Facility Southern Great Plains site. Mesoscale and microscale structures will be sampled with a variety of aircraft, …
Date: June 30, 2007
Creator: Miller, M. A.; Avissar, R.; Berg, L. K.; Edgerton, S. A.; Fischer, M. L.; Jackson, T. et al.
Object Type: Report
System: The UNT Digital Library
International Collaboration on CO2 Sequestration (open access)

International Collaboration on CO2 Sequestration

On December 4, 1997, the US Department of Energy (USDOE), the New Energy and Industrial Technology Development Organization of Japan (NEDO), and the Norwegian Research Council (NRC) entered into a Project Agreement for International Collaboration on CO{sub 2} Ocean Sequestration. Government organizations from Japan, Canada, and Australia, and a Swiss/Swedish engineering firm later joined the agreement, which outlined a research strategy for ocean carbon sequestration via direct injection. The members agreed to an initial field experiment, with the hope that if the initial experiment was successful, there would be subsequent field evaluations of increasingly larger scale to evaluate environmental impacts of sequestration and the potential for commercialization. The evolution of the collaborative effort, the supporting research, and results for the International Collaboration on CO{sub 2} Ocean Sequestration were documented in almost 100 papers and reports, including 18 peer-reviewed journal articles, 46 papers, 28 reports, and 4 graduate theses. These efforts were summarized in our project report issued January 2005 and covering the period August 23, 1998-October 23, 2004. An accompanying CD contained electronic copies of all the papers and reports. This report focuses on results of a two-year sub-task to update an environmental assessment of acute marine impacts resulting from …
Date: June 30, 2007
Creator: Israelsson, Peter H. & Adams, E. Eric
Object Type: Report
System: The UNT Digital Library
Remark On: The Neutron Spherical Optical-Model Absorption. (open access)

Remark On: The Neutron Spherical Optical-Model Absorption.

The energy-dependent behavior of the absorption term of the spherical neutron optical potential for doubly magic {sup 208}Pb and the neighboring {sup 209}Bi is examined. These considerations suggest a phenomenological model that results in an intuitively attractive energy dependence of the imaginary potential that provides a good description of the observed neutron cross sections and that is qualitatively consistent with theoretical concepts. At the same time it provides an alternative to some of the arbitrary assumptions involved in many conventional optical-model interpretations reported in the literature and reduces the number of the parameters of the model.
Date: June 30, 2007
Creator: Smith, A. B.
Object Type: Report
System: The UNT Digital Library
Hydrogen Production via a Commerically Ready Inorganic membrane Reactor (open access)

Hydrogen Production via a Commerically Ready Inorganic membrane Reactor

It has been known that use of the hydrogen selective membrane as a reactor (MR) could potentially improve the efficiency of the water shift reaction (WGS), one of the least efficient unit operations for production of high purity hydrogen from syngas. However, no membrane reactor technology has been reduced to industrial practice thus far, in particular for a large-scale operation. This implementation and commercialization barrier is attributed to the lack of a commercially viable hydrogen selective membrane with (1) material stability under the application environment and (2) suitability for large-scale operation. Thus, in this project, we have focused on (1) the deposition of the hydrogen selective carbon molecular sieve (CMS) membrane we have developed on commercially available membranes as substrate, and (2) the demonstration of the economic viability of the proposed WGS-MR for hydrogen production from coal-based syngas. The commercial stainless steel (SS) porous substrate (i.e., ZrO{sub 2}/SS from Pall Corp.) was evaluated comprehensively as the 1st choice for the deposition of the CMS membrane for hydrogen separation. The CMS membrane synthesis protocol we developed previously for the ceramic substrate was adapted here for the stainless steel substrate. Unfortunately no successful hydrogen selective membranes had been prepared during Yr I …
Date: June 30, 2007
Creator: Liu, Paul
Object Type: Report
System: The UNT Digital Library